Twin Mikunis

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After much consideration, I'm thinking that my plans for a twin choke weber on my 750 racer may be a bit complicated and I may now fit a pair of 34mm Mikuni VM carbs.

However, the dimensions given on their website suggest that they are too wide to fit side by side on the Norton head.
They are 83 mm wide, and the distance between the ports is about 70mm, so I don't see how they can fit.

I know that a pair of 32mms on a Commando is a common mod , and they are the same size carb bodies....so how do they fit?????
 

MichaelB

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They use special offset manifolds. I don't see how velocity stacks will fit as they will hit the frame. I have only seen one with filters and they were offset foams that tucked inside the frame rail.

Amal Mk 2's fit nicley and you can run stacks. I believe Mick Hemmings runs 36's on his racer.
 
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Thanks for that info. Does the offset in the manifolds look like it will upset the gas flow?
I use 36mm mk2s at the moment , but the mid range is not too good. It will not accept full throttle below 4000 so I'm thinking smaller carb would help with that. The kind of circuits I use it on are fairly short and twisty so mid range is more important that all out top end power.
 
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Nah mate they should look like this....no air filters!

http://i5.photobucket.com/albums/y178/p ... rton03.jpg

As you can see they are both right hand carbs, I was given them by a friend. That makes it a bit hard to set up for idle.

It shows rich on the mid range on the dyno, but weakening the needles doesn't help. Consensus is that the (non adjustable) air correctors are wrong, or maybe there's not enough air speed to atomise the fuel at lowish rpm.
The carbs are a bit worn anyway and I thought I'd try something different.
 

MichaelB

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John, Didn't realize you were running a featherbed. Looks like you may have enough room to run Mic's with stacks.
The offset is a slight bend. Logic tells me a slight bend is not as clean as a straight shot but I have also learned logic doesn't always work with air flow, so I don't know.
If you wish, I have a project Commando I could mock up show how if fits on a Commando. If you would like for me to do this, PM me your e-mail and I'll do it next week. I am not techy enough to post pix on the web site.
 
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